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Ask UsMini Implants in Anterior Mandible: Expectations of Longevity?
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Anon. asks:
I have been restoring implants for 6 years. I had never placed one because of the complexity of the anatomy and the armamentarium. However, I have now taken courses for mini implants and have placed them in sawdust mandibles. This is quite a bit simpler, than conventional implants, and requires far less equipment. I am thinking of restricting my use to the anterior mandible for supporting overdentures. I am concerned about longevity. For those of you actually doing this, what are your expectations for longevity? What, if any, complications have you experienced in placing these implants?
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15 Responses to “ Mini Implants in Anterior Mandible: Expectations of Longevity? ”
I have been placing these implants for 6 years. Survival rates up to one year have been around 90%, all immediately loaded. For fixtures that have survived 1 year, all have survived. However, some patients, especially those who had a knife edge ridge in the mandible that we did not flatten, have lost up to 30% of the initial crestal bone. This is the minority of patients, and most have lost far less than this.
these alloy implants never integrate, failure rates are too high compared to standard tested fixtures, unskilled clinicians should always reflect a flap to see ridge, flatten and prepare sites. if adequate width, traditional fixtures with documented long ter success should be used, warrantees are there from manufacturers.minis failtoo often then what to do,replace for free, companies dont replace
I have been placing Minis for about 8 years. I would suggest the more aggressive threads, use a stent, and check your osteotomy with a perio probe before inserting. I have done all of this and still I get failures. I would estimate about 80% success. Also it is ideal to make sure that the minis are not off angle since it will wear out the O rings too fast. Be selective to your cases and prewarn the pt that conventional implants have a higher success rate. When they work you have done a great service. When they fail others can be placed or switch to conventional. I tell my patients that if the mini fails I will do it again if they want but they will have to pay even if it only lasts a few months. I make them sign this agreement.
Placing standard fixture implants in the anterior mandible is a procedure that any clinician who performs dentoalveolar surgery, should be able to perform with a success rate in the high 90’s. Using the mini implants as a substitute for them is a disservice to the patient.
Minis were built as transitionals…eventhough they have been FDA approved, I would stay away from them for for restorations. Theybwill never be adequate to support a full denture for long term use.
I have friends that have placed them and they are continually seeing more bone loss and usually have 1-2 minis break within 2-5 years. The companys say no big deal when this happens and to put another one next to the broken one. To get ideal functionality and great clinical results then you hve to place a lot of them side by side which increases your cost and us a lot more work.
Larger implants give more support….period! Physics will back up that statement. Do the right thing for your patients…give them the proper treatment they deserve.
The FDA should be ashamed of themselves for letting this slip by….however it is obviously not the first thing to slip by them.
To end thus discussion…would you feel more safe driving on a bridge that is supported by toothpicks or by 8×8 pillars?
I’ve been placing implants for 24 years with very good success rates. Vey rarely a failure. I tried “mini’s” for mandibular overdentures along with one of my associates. Most in good jaws. We’ve both stopped placing them. We experienced too many failures. Absolutely followed the manufacturers protocal and were very careful to avoid surgical complications. Had to replace them with standard implants when this occured. I can’t explain the reason for our failures when others are touting their success rates. We have a lot of surgical experience. But as a caution I will say working blind if you are inexperienced can lead to surgical errors and immediately loading them in function without rigid splinting does seem to violate the principles that we have followed for successful osseointegration.
I first started to use minitransitional implants about 14 years ago, when Victor Sendax, who accidentally discovered the minitranstional implant philosophy, decided to use Dentatus Titanium posts that were intended for use in restoring endodontically treated teeth; and used them to help out the late Luciano Pavorotti, when an exisitng conventional fixed bridge failed because of rotted natural abutment teeth. He was able to place these titanium posts into the edentulous areas and drilled holes through the pontics of the bridge and stabilized the bridge.
Bernard Weisman, the owner of Dentatus, worked with Sendax, and was the first company to coin the term Mini Transitional Implants.
As the name suggests, their purpose was really intended to be used as a transitional proceedure until a more definitive solution was found.
These narrow diameter implants ( initially 1.8mm in diameter) turned out to be so beneficial because of the simplicity of the surgery, and the ease of inserting them, and the fact that were immediately loaded…..contrary to the Branemark philosopy.
Initially, they were made from pure surgical grade titanium, and in my esperience, even if they did achieve some degree of osseointegration, there was always the risk of fracture, because of the softness of the titanium.
Several implant companies have picked up on these small diameter implants, have increased the diameter, and have made them from titanium alloy.
Dentatus has an Atlas Kit, that allows the minis to be placed non parallel, whereby the retention is via a silicone lining inserted into the trough cut into the existing denture.
I would agree with some of the above comments, in that given the choice, I would prefer to use a narrower conventional implant with conventional prosthetic options in situations requiring absolute osseointegration, and not take the risk…….but minis have their place, and the patients have to be informed of their limitations.
Gerald Rudick dds Montreal, Canada
I am alarmed to see so many of experienced surgeons refraining from mini implants as overdenture abutments. I have worked under a prosthodontist for 3 years and i have known him for 10years, he has been using Mini Implants for supporting overdentures with more than 95% success. i have a case lined up in 2 weeks, and now i am tensed whether to go ahead.
If please anyone can guide me what precautions to take apart from Informed Consent from patients, it will be useful for me…
It is surprising to hear statements that “mini dental implants dont integrate”, specially coming from an oral surgeon!
Another interesting statement “Minis fail too often”. Probably in your hands!
If you look at the surface treatment of a mini dental implant (not all of them but most reputable brands) you will find that the surface is sand blasted and acid etched, the alloy is titanium CpV (stronger), then the question if you got more than 35 nw of primary stability would be Why wouldnt they integrate? if all the conditions are there?
Our experience with minis (and we use from 1.8 minis to 6.5 wide implants, has been extremely good.
Of course we have had failures, every system does have failures.
But in the anterior mandible the success rate is even better than that of regular implants.
There is always the same issue here, why do some people get extremely good results and some others dont?
Biomechanics- surface area- primary stability- prosthetic knowledge etc.
Most people placing minis have not taken a course for minis, and minis are very technique sensitive, there are a lot of specific considerations to be respected.
Dont expect to be the super surgeon and shift to minis and have success, in minis the advantage is to the one with the knowledge in applied loads.
Go back to the book of Dr Mish (contemporary implant dentistry and read the biomechanics chapter, then translate that to a thinner device and to strategies to distract and divert the forces to the ridges and soft tissues instead to cantiliber the whole denture from the minis)
It must be understood that inspite of the Mini’s being touted as an easy system for implant placement ..their placement is actually very technique sensitive
The branemark protocol does NOT apply
For example the MDI (Imtec) protocol has the following clearly stated protocols (variations will apply )
There are many other steps but the following come to mind as examples of differences and common mistakes
1) Always attempt bi cortical fixation
In case of ant mandible go to within 3mm of inferior border
In some cases minis can engage lingual plate to get the bi cortical fixation
Maxillary cases engage sinus floors
2)Drill with first and only drill thru cortex only ..less than one third the length of implant..do not drill to full depth
b) very slow application of force thru finger driver to advance Mini
DO NOT use torque wrench until last couple of threads and do 0.25 turn every 30 seconds
3) Extreme care for prosthetic design
In over dentures if the denture is not retrofitted and put back into occlusion as before (use bite registration) you are making a 12 unit fixed bridge on 4 tooth picks .. which WILL fail
Implants” retain” the denture not support it ..this is the most common mistake we make
In fixed cases you need to be very comfortable with Biomechanics of prosthetic design (previously reffered to text by Misch is excellent)
At the end of the day titanium will integrate but every engineered design will have limitations ..we simply must learn the designs
There is also a tendancy to abuse the minis as we feel they are so simple they are not worthy of our specialised expertise ..I can understand that having been thru the learning curve ..but for precisly the reason that they are so small and simple they need our utmost attention .
I also understand that mini implant sales world wide are 50% of all implants sold ..sound high but I bet its not far wrong
Thank you very much Dr sengupta & Dr Alvaro - both of you have infused confidence in me now, i also understand that everyone has to go thru the learning curve, I am going ahead with the case and have planned to place 4 mini Imtec implants supporting the lower denture… shall keep posted about the progress.
Which are the top most reputed Mini Implant brands. Who gives good support?
I am happy to hear that!
keep in touch I believe you have access to my personal email!
As for the players, I have to admit I have been placing imtec mini implants since they became available in the market at the end of the nineties and I am extremely happy , but before that I got in 1994 a mini implants kit in Brasil, “Diamond” (no comments).
I believe the actual top players in the market with quality products would be: Imtec, Dentatus, Sterngold and Intralock. There are more systems available in the market, maybe way so many.
The Sterngold system would be the one different to the other ones since the attachment system is different with some advantages and disadvantages over the other three.
Talking about which one has been available longer of the four systems in question? The evidence I have collected demonstrate that the Dentatus system was the initial system used by Dr Sendax.
I hope this helps.
I can only agree that mini implants are actually much much more difficult to place than conventional implants and because they are placed using flapless surgery it makes them even more difficult. They are not an easy option as people think.
Thanks for the info of all of you pioneers out there. I just got into the “mini implant” ball game and am having a case coming up : FLD RETAINED by 4 or 5 Imtec MDI… “Retained, NOT supported” seems to be a most important factor to avoid failure of the MDI.
So my quesstion is, should we process both dentures first, go through all the routine until the patient is completely comfortable, painfree with the new prosthesis… then place the implants and retrofit the denture. That way , all the adjustment and removal of the acrylic do not inadvertently turn the retainers into supporters.
Please help!
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